Varying dependency of periplasmic peptidyl-prolyl cis/trans isomerases in promoting Yersinia pseudotuberculosis stress tolerance and pathogenicity

Ikenna R Obi , Roland Nordfelth , Matthew S Francis (1)

1 Department of Molecular Biology [Umeå]

Periplasmic peptidyl-prolyl cis/trans isomerases (PPIases) catalyze the cis/trans isomerization of peptidyl-prolyl bonds, which is a rate-limiting step during protein folding. We demonstrate that the surA, ppiA, ppiD fkpA and fklB alleles each encode a periplasmic PPIase in the bacterial pathogen Yersinia pseudotuberculosis. Of these, four were purified to homogeneity. Purified SurA, FkpA and FklB, but not PpiD, displayed detectable PPIase activity in vitro. Significantly, only Y. pseudotuberculosis lacking surA caused drastic alterations to the outer membrane protein profile and fatty acid composition. They also exhibited aberrant cellular morphology, leaking LPS into the extracellular environment. The SurA PPIase is therefore most critical for maintaining Y. pseudotuberculosis envelope integrity during routine culturing. On the other hand, bacteria lacking either surA or all of the genes ppiA, ppiD, fkpA and fklB, were sensitive to hydrogen peroxide and were attenuated in mice infections. Thus, Y. pseudotuberculosis exhibits both SurA-dependent and SurA-independent requirements for periplasmic PPIase activity to ensure in vivo survival and a full virulence effect in a mammalian host.

Mots clés: Life Sciences

Ikenna R Obi, Roland Nordfelth, Matthew S Francis. Varying dependency of periplasmic peptidyl-prolyl cis/trans isomerases in promoting Yersinia pseudotuberculosis stress tolerance and pathogenicity. Biochemical Journal, 2011, 439 (2), pp.321-332. ⟨10.1042/BJ20110767⟩. ⟨hal-00628676⟩